In a number of applications, such as mixtures of different liquids, it may be necessary to release and mix an additive powder, gel or liquid into another liquid shortly before the liquid mixture is used. It may not be possible or desirable to store the products in a premixed form, as they may react undesirably with each other when stored as the mixture for a period of time. An example of this may be two component pharmaceuticals which have a longer shelf life when unmixed than they do when mixed. However, it can also apply to other liquids or to mixtures of liquids and gases, such as water, alcoholic beverages, other beverages, and other solvents or solutions. The liquid to which the additive liquid is introduced may be a carbonated or a non-carbonated liquid.
A closure device for releasing an additive liquid into a liquid in a container by operation of the closure device is known from the prior art. International Patent Application WO2007/129116 discloses a closure device for use with a container having a main liquid compartment and an opening with a neck. The closure device has a cap member defining a fluid chamber and a housing having a plug member. The plug member seals an aperture in the bottom wall of the fluid chamber. The plug member includes a nozzle directed away from the fluid chamber. When the cap member is turned it is lifted relative to the housing from a closed position in which the plug member closes the aperture to an open position in which the plug member is withdrawn from the aperture and provides a communication path for fluid in the fluid chamber to pass through the nozzle to the main liquid compartment.
The prior art closure device requires a separately formed bottom wall of the closure, since the portion surrounding the aperture in the bottom wall must be of a relatively flexible material to provide an effective seal with the plug member. This can increase the complexity of manufacture.
The prior art closure device requires a seal between the housing and the neck of the bottle, and an additional seal between the housing and the fluid chamber, to maintain pressure inside the main liquid compartment when the container is used with a carbonated beverage.
Once the prior art closure device is removed from the neck of the container, the liquid in the fluid chamber of the cap member can drip from the nozzle, since the cap member remains in its open position.